AM3517/AM3505 ZCN package ball change in Rev. E datasheet

john5123

Other Parts Discussed in Thread: AM3505

The Revision History in the latest datasheet for "AM3517/05 Sitara ARM Microprocessors (Rev. E)" (sprs550e.pdf) show ball N22 of the ZCN package changing from NC to VDDS. Is there any advantage in changing an existing PCB design to connect N22 to VDDS, or can it safely be left unconnected? What brought about this change?

By the way, Table 2-27 on page 79 of the datasheet hasn't been updated to include N22 in the list of VDDS balls yet.

Thanks,
John

over 12 years ago

0 yimin bai1 over 10 years ago

Expert 1495 points

Hi Sir

Does any expert can answer this question ?

We used AM3505 ZCN package to develop product and it has been on sale for several years.

Currently we met RMA issue and would like to know why pin N22 should be connected with VDDS.

In our design ,we followed spec SPRS550C to leave N22 NC.

please advise there is any side effect if we leave N22 pin as NC.

Thanks in advance.

Yimin

0 Biser Gatchev-XID over 10 years ago in reply to yimin bai1

TI__Guru**** 393215 points

Quoting from another thread (https://e2e.ti.com/support/arm/sitara_arm/f/791/t/236921 ):

"When using the DSI PLL on the ZCN package, you need to supply N22 with 1.8V and provide a 1uF decoupling cap to ground on N21. These supplies are used for the DSI PLL."

0 yimin bai1 over 10 years ago in reply to Biser Gatchev-XID

Expert 1495 points

Hi Sir

thanks for your reply.

In our design, we left the N22 pin as NC. Is there any side effect or concern ?

BR
Yimin

0 Biser Gatchev-XID over 10 years ago in reply to yimin bai1

TI__Guru**** 393215 points

If you don't see DSI PLL issues, there are no other side effects. Check the other thread for details.

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AM3517/AM3505 ZCN package ball change in Rev. E datasheet